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Cannot create Video conference bridge on 2921

Florian Zahn
Level 4
Level 4

Hi,

i want to setup a homogenous video conference bridge on my Cisco 2921 running 15.2(4)M1, but I am not able to get this working, because when setting up

the dspfarm profile, i have to enter "maximum sessions". The only value I can select here is "0".

According DSP calculator I should have enough DSPs for this.

I have a PVDM3-16 and a PVDM3-32. In the same router are 8 BRI installed (4x VIC2-2BRI-NT/TE).

Here is "show inventory":

NAME: "CISCO2921/K9", DESCR: "CISCO2921/K9 chassis, Hw Serial#: FCZ164260UQ, Hw Revision: 1.0"
PID: CISCO2921/K9      , VID: V07 , SN: FCZ164260UQ

NAME: "2nd generation two port BRI voice interface daughtercard on Slot 0 SubSlot 0", DESCR: "2nd generation two port BRI voice interface daughtercard"
PID: VIC2-2BRI-NT/TE   , VID: V03 , SN: FOC16326K2U

NAME: "2nd generation two port BRI voice interface daughtercard on Slot 0 SubSlot 1", DESCR: "2nd generation two port BRI voice interface daughtercard"
PID: VIC2-2BRI-NT/TE   , VID: V03 , SN: FOC16326K6F

NAME: "2nd generation two port BRI voice interface daughtercard on Slot 0 SubSlot 2", DESCR: "2nd generation two port BRI voice interface daughtercard"
PID: VIC2-2BRI-NT/TE   , VID: V03 , SN: FOC15492F5P

NAME: "2nd generation two port BRI voice interface daughtercard on Slot 0 SubSlot 3", DESCR: "2nd generation two port BRI voice interface daughtercard"
PID: VIC2-2BRI-NT/TE   , VID: V03 , SN: FOC16326K9L

NAME: "PVDM3 DSP DIMM with 32 Channels on Slot 0 SubSlot 4", DESCR: "PVDM3 DSP DIMM with 32 Channels"
PID: PVDM3-32          , VID: V01 , SN: FOC16392D4G

NAME: "PVDM3 DSP DIMM with 16 Channels on Slot 0 SubSlot 5", DESCR: "PVDM3 DSP DIMM with 16 Channels"
PID: PVDM3-16          , VID: V01 , SN: FOC16277ZL1

NAME: "C2921/C2951 AC Power Supply", DESCR: "C2921/C2951 AC Power Supply"
PID: PWR-2921-51-AC    , VID: V03 , SN: DCA1630K0DP

Here is "show dsp-group all":

DSP groups on slot 0:
dsp 1:
  State: UP, firmware: 32.1.0
  Max signal/voice channel: 32/32
  Max credits: 480, Voice credits: 15, Video credits: 465
  num_of_sig_chnls_allocated: 0
  Transcoding channels allocated: 0
  Group: FLEX_GROUP_VOICE, complexity: FLEX
    Shared credits: 15, reserved credits: 0
    Signaling channels allocated: 0
    Voice channels allocated: 0
    Credits used (rounded-up): 0
  Group: FLEX_GROUP_VIDEO_POOL, complexity: FLEX
    Video Credits Max: 465, Share: 465, Reserved (rounded-up): 0
    num_video_bridge: 0, num_video_codec: 0
    num_audio_xcoder: 0, num_synvideo: 0, num_vqm: 0
  Slot: 0
  Device idx: 0
  PVDM Slot: 0
  Dsp Type: SP2600

dsp 7:
  State: UP, firmware: 32.1.0
  Max signal/voice channel: 16/16
  Max credits: 240, Voice credits: 240, Video credits: 0
  num_of_sig_chnls_allocated: 16
  Transcoding channels allocated: 0
  Group: FLEX_GROUP_VOICE, complexity: FLEX
    Shared credits: 240, reserved credits: 0
    Signaling channels allocated: 16
    Voice channels allocated: 0
    Credits used (rounded-up): 0
  Slot: 0
  Device idx: 0
  PVDM Slot: 1
  Dsp Type: SP2600

slot 0: total video credits: 465; reserved/used: 0 (0%)

DSP groups on slot 1:
This command is not applicable to slot 1

  0 DSP resource allocation failure

I want to setup as follows:

voice-card 0

voice-service dsp-reservation 34

dspfarm

dspfarm profile 10 conference video homogeneous 

codec g711ulaw

codec g711alaw

codec g729ar8

codec g729abr8

codec g729r8

codec g729br8

codec h264 cif frame-rate 30 bitrate 320kbps

associate application SCCP

shutdown

  <0-0>  Number of sessions assigned to this profile

dspfarm profile 10 conference video homogeneous 
codec g711ulaw
codec g711alaw
codec g729ar8
codec g729abr8
codec g729r8
codec g729br8
codec h264 cif frame-rate 30 bitrate 320kbps
associate application SCCP
shutdown

When I now try to set maximum-sessions:

  <0-0>  Number of sessions assigned to this profile

Any ideas, why this is not working?

Thanks for help!

Florian

2 Accepted Solutions

Accepted Solutions

Well, you have reserved 34% of PVDMs to voice via:

voice-service dsp-reservation 34,

which yields 16.32 channels which essentally allocates 2 DSPs (PVDM3-32) as a DSP cannot be shared between TDM voice channels and conferecences.

perhaps try changing this to something lower, i.e. 33.

Q. What does the CLI "voice-service dsp-reservation" do?

A. The voice service DSP reservation CLI allows you to specify the  percentage of DSPs to be reserved for voice and time-division  multiplexing (TDM) applications. The total number of DSP resources  installed in the router during bootup is dynamically calculated by Cisco  IOS Software. The value entered here is taken as the percentage of  available resources reserved for voice. The remaining resources are  automatically reserved for video. This CLI ensures voice services are  provided with adequate resources to function. You cannot reserve all  resources for video when analog interfaces are installed on the router.

Also, is there is reason you have G729, etc codecs defined in homogeneous  profile?

Chris

View solution in original post

I think this document explains why you can't setup a VC bridge. It been updated in October 2012, so it's really resent. http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6555/ps6602/whitepaper_C11-718333.pdf

According to it you can't have a fragmented DSP core, aka use the same core for both voice and video. Each of your PVDM3 modules have one core and if you use 40 channels of the total 48 for voice you would use both cores for voice, therefor you can't allocate the remaining 8 channels to the VC bridge.

If I calculate 34% of 48 I get just above 16. So at least 16+1 channel is allocated by the voice-service dsp-reservation 34 command.

Please remember to rate all useful posts.

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View solution in original post

15 Replies 15

Chris Deren
Hall of Fame
Hall of Fame

How do you figure you have enough DSPs? 4 BRI cards by themselves will use the PVDM3-32, here is what I get with the calc:

This is for 1 video bridge -4 participants - 1 class  - homogeneous 

Hi Chris,

thanks for your reply.

4 BRI-cards are 4x2x2 channels = 16 G.711 channels (low complexity should be enough, because for ISDN it is only G.711)

This means the PVDM3-32 is left for video

And also on your calculation there are still only 40 DSPs needed and I have 48

DSP-Calc recommends a PVDM3-64, because it always trys to save slots. So to fullfill 40 DSP, it recommends a PVDM3-64

But I think, you should also be able to use a PVDM3-16 and a PVDM3-32. Then there are not 24 available, but only 8....

Or do I forget anything?

Thanks and

Regards

Florian

Well, you have reserved 34% of PVDMs to voice via:

voice-service dsp-reservation 34,

which yields 16.32 channels which essentally allocates 2 DSPs (PVDM3-32) as a DSP cannot be shared between TDM voice channels and conferecences.

perhaps try changing this to something lower, i.e. 33.

Q. What does the CLI "voice-service dsp-reservation" do?

A. The voice service DSP reservation CLI allows you to specify the  percentage of DSPs to be reserved for voice and time-division  multiplexing (TDM) applications. The total number of DSP resources  installed in the router during bootup is dynamically calculated by Cisco  IOS Software. The value entered here is taken as the percentage of  available resources reserved for voice. The remaining resources are  automatically reserved for video. This CLI ensures voice services are  provided with adequate resources to function. You cannot reserve all  resources for video when analog interfaces are installed on the router.

Also, is there is reason you have G729, etc codecs defined in homogeneous  profile?

Chris

Hi Chris,

I tried so set a lower value for "voice-service dsp-reservation", but 34 was the lowest possible value.

As far as i know, the information that, DSP cannot be shared betwen TDM and conference ressources is not valid anymore for PVDM3, since a new firmware is used, that provides all services:

Q.

Can conferencing, transcoding and voice calls be supported on a single DSP?

A. Yes. The PVDM3 modules have a universal firmware image that allows sharing DSP resources between transcoding, voice, and conference calls. On the PVDM2 you can use the same DSP for voice and transcoding calls, but a different DSP firmware image is required for conference calls requiring a DSP to be dedicated when conferencing is configured.

Anyway: my BRI-cards do not use the full PVDM3-32 and the PVDM3-16 should still be enough for one video-conference-profile:

ABout the audio-codecs: IOS installed them by itself when I created the dspfarm-profile.

Regards

Florian

Even if a lot of codecs get automatically added once you do a conference dspfarm-profile you can manually remove them. The profile need to be shutdown and can't have any max session statement to be able to remove them.

All g729 codecs with a "b" in the name should always be removed if you don't need to use VAD. A golden rule is VAD is BAD.

Please remember to rate all useful posts.

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Hi Roger,

thanks for this information about the "b"-codecs... I will remote them.

But I can still not enable video conferencing services...

Regards

Florian

I've never setup a VC conf bridge on a G2 ISR, so I have no first had info on how to do it. But I found this post with a little digging with Google. http://www.ccierants.com/2011/12/cisco-isr-g2-video-conferencing.html?m=1

Take a look at it and report back if there were any useful info in it.

Please remember to rate all useful posts.

Sent from Cisco Technical Support iPhone App



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In the link on the blog I saw this explanation of when you see a 0 (zero) after the max session command.

Q. Why do I get maximum-sessions 0 after configuring the required codecs?
A. Display of maximum-sessions 0 while configuring your dspfarm indicates that not enough DSP resources are available. You can try to remove certain codecs from your profile or add additional DSP resources. Please use the DSP calculator to calculate the number of DSPs you need.

To me that indicate that you either don't have enough DSPs or need to remove some codecs from the dsp profile. All g729 with b in the name are a higher complexity codecs than the other. So these would require more dsp resources. Also the minimum amount you can setup for video based on the FAQ seem to be 4, check with the dsp calculator that you have enough PVDM3 modules for this.

Please remember to rate all useful posts.

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Hi!

I have a strange issue about dsp reservation:

Router(config-voicecard)#voice-service dsp-reservation ?

  <100-65520>  percent of dsps to reserve for voice-only services and TDM video services

I cannot configure a percente under 100.

IOS version  c2900-universalk9-mz.SPA.152-2.T1.bin.

PVDM3 128

Any ideas about this?

Thanks,

Mirko

Florian Zahn
Level 4
Level 4

Hi Roger,

As I already wrote, I have 48 DSP and according DSP Calculator 40. DSP should be enough. I alread removed the G729xxx codecs, but this did not solve the problem

Regards

Florian

Sent from Cisco Technical Support iPhone App

I think this document explains why you can't setup a VC bridge. It been updated in October 2012, so it's really resent. http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6555/ps6602/whitepaper_C11-718333.pdf

According to it you can't have a fragmented DSP core, aka use the same core for both voice and video. Each of your PVDM3 modules have one core and if you use 40 channels of the total 48 for voice you would use both cores for voice, therefor you can't allocate the remaining 8 channels to the VC bridge.

If I calculate 34% of 48 I get just above 16. So at least 16+1 channel is allocated by the voice-service dsp-reservation 34 command.

Please remember to rate all useful posts.

Sent from Cisco Technical Support iPhone App



Response Signature


Hi Roger,

I think the thing with the DSP cores is not valid anymore for PVDM3:

Q.

Can conferencing, transcoding and voice calls be supported on a single DSP?

#

A. Yes. The PVDM3 modules have a universal firmware image that allows sharing DSP resources between transcoding, voice, and conference calls. On the PVDM2 you can use the same DSP for voice and transcoding calls, but a different DSP firmware image is required for conference calls requiring a DSP to be dedicated when conferencing is configured.

I think I will create a TAC case regarding this issue...

Thanks all for help

Regards

Florian

A. Yes. The PVDM3 modules have a universal firmware image that allows sharing DSP resources between transcoding, voice, and conference calls.

This is only my interpretation of this and the other links in this post, so I can be wrong, but anyway here goes what I think is the problem in your case.

The part you reference from in the FAQ “talks” about the ability for PVDM3 modules to handle mixed voice resources, as transcoding, TDM to/from VoIP, and conference would be. But in the link I referenced it “talks” about the ability to mix voice and video resources on PVDM3 modules. See below snipplet from the document I linked to previously.

IPSLA VO presently cannot use fragmented cores. A fragmented core is one that is allocated for both voice and video. This needs to be taken into consideration when procuring/provisioning PVDM3.

But a TAC case would be of interest, so that we can get an official take from Cisco on this. Please update when you have got an answer from TAC.

Please remember to rate helpful responses and identify helpful or correct answers.



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hi Roger,

thanks for the explanation, but I do still think, that I should be able to setup a video conference brige....:

1. According to figure 1 on your datasheet, indeed a DSP core can be fragmented for voice and video. Only for IPSLA-operation

this is not allowed, because a special image for this core is used.

2. My router has two PVDM3-moules: One PVDM3-16 and a PVDM3-32. The PVDM-32 should be totally enough to fullfill the requirements of 16 BRI-channels (4x VWIC2-2BRI-NT/TE). So the whole PVDM3-16 is unused andis free for video-conference bridge. According Cisco documetation the PVDM3-16 can run a homogenous video conference bridge, but not a heterogenous bridge. But I am not able to configure the homogenous bridge...

I opened the TAC case and lets see for a definitive answer....

Regards

Florian

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